1. Field
Neonatal electrocardiogram screening.
2. Background
Long QT syndrome (LQTS) is a genetic disease characterized by an abnormally prolonged QT interval in the electrocardiogram (ECG) waveform. LQTS is a leading cause of sudden cardiac death in the young. When infants with undiagnosed LQTS die, their sudden deaths are often labeled as sudden infant death syndrome (SIDS) because no apparent cause of death could be found by autopsy. Using post-mortem genetic analysis, researchers have found that more than 10% of SIDS cases are actually due to undiagnosed LQTS. LQTS can be diagnosed by a routine 12-lead ECG. Once diagnosed, the treatments for LQTS, including beta-blocker therapy and internal cardiac defibrillator (ICD), are very effective in preventing cardiac arrhythmia and sudden death. Therefore, some European countries are considering the possibility of introducing neonatal (days 15-25) ECG screening as part of their National Health Services. Among the European countries, Italian Ministry of Health funded an electrocardiogram (ECG) screening program on over 50,000 babies to assess the feasibility and outcomes of a nationwide neonatal ECG screening. The program has been tremendously successful, and such success has generated enthusiasm toward implementation of a nationwide screening program from many European nations and the United States.
Since the proposed screening ECGs are targeted at two to four weeks of life, the screenings for LQTS proposed will likely have to be done at a pediatrician's office. Most nurses or nurse's assistants are not trained to perform newborn ECGs. A regular ECG machine has 10 long cables which often tangle among themselves. When conducting an ECG test, the operator needs to place 10 electrodes (stickers) on the patient and match the cables with each respective electrode on the patient. This process of untangling the cables, placing electrodes, and matching the cables and electrodes takes skill and time.
Performing an ECG on a newborn is challenging and often takes up to 20 minutes or more. Placing the leads on a newborn is difficult because of limited space on the torso and the babies are not cooperative. Furthermore, performing an ECG on a newborn using the current complicated leads system by inexperienced nurses is prone to error, such as wrong leads placement, artifacts, and inadequate ECG signal acquisition.
To solve the issues with improper leads placement and tangling of cables, prior inventions have used pre-positioned leads or one-piece design. U.S. Pat. Nos. 4,608,987 and 5,224,479 describe a vest containing pre-positioned leads, which is cumbersome to use in babies and requires a large area of skin contact when worn. Chest strip designs have been proposed by U.S. Pat. Nos. 4,233,987, 5,184,620, and 5868671. The limitations of these designs are that they are not designed for use in newborns and infants; and only three to six chest leads are typically provided (e.g., the strips lack limb leads) and therefore cannot be used for QT analysis. U.S. Pat. No. 6,847,836 proposes a one-piece chest pad design for use of ECG monitoring in the emergency room. The chest pad design is not specific for newborns and infants, and has a large skin contact area, which is an important limitation for use in babies because of their sensitive skin. Furthermore, the limb lead positions in the chest pad design of U.S. Pat. No. 6,847,836 are not generally proper for accurate measurement of QT intervals on a 12-lead ECG. As a result, QT analysis using such a design and system is not generally accurate.
ECG is mostly performed in adults, especially elderly people. ECG on newborns used to be a rare practice. None of the current ECG machine or leads system is designed for use in newborns or infants. As many nations are considering implementing a nationwide newborn ECG screening program, there is an urgent need for a simple, quick and error-proof ECG leads system for newborns. The current design is an ECG leads system specifically designed for newborns to be used in pediatrician's office or hospital for newborn screening.